Some internal combustion engines utilize power take-off systems for powering auxiliary components, such as fuel and hydraulic pumps. Generally, power take-off systems harness a portion of the torque generated by an internal combustion engine and transfer the harnessed torque to one or more auxiliary systems using a gear train. Typically, the gears of the gear train are maintained in meshing engagement with each other within a housing. Desirably, an interior of the housing is supplied with a lubricant, such as oil, to lubricate the gears. The lubricant reduces friction and wear between meshing gears. Commonly, the lubricant is sealed within the housing to prevent leakage of the lubricant from the housing.
During operation of a power take-off system, the pressure of air within the housing may fluctuate based on operating conditions of the internal combustion engine. Generally, as the temperature of the air within the housing increases, the pressure of the air within the housing correspondingly increases. The temperature of the air within the housing may increase based on changes in the load placed on the internal combustion engine, changes in ambient temperature, and changes in other operating conditions of the engine. Modest pressure fluctuation within the housing of a power take-off system likely does not negatively affect the performance of the system. However, negative consequences (e.g., breakdown of seals, bearings, and the like) may result should the pressure within the housing reach or exceed certain pressure thresholds of the system.
Many conventional power take-off systems are equipped to vent air from the housing to compensate for extreme increases in pressure within the housing. Some systems vent air directly into the atmosphere. While such system may be effective at reducing the pressure within the housing, the air released from the housing into the atmosphere often contains lubricant. Accordingly, venting air from within the housing of a power take-off system directly into the atmosphere results in leakage of the lubricant, as well as a negative impact on the environment in the form of undesirable emissions.